*{
    margin: 0;
    padding: 0;
    box-sizing: border-box;
}
/* 使用弹性讲内容居中 */
body{
    display: flex;
    justify-content: center;
    align-items: center;
    min-height: 100vh;
    background: black;
}
.d1 {
    position: relative;
    width: 200px;
    height: 200px;
    border-radius: 50%;
    background: linear-gradient(to right,transparent 50%,greenyellow);
    animation: nice 2s linear infinite;
}
/* 动画 */
@keyframes nice{
    from{
        transform: rotate(0deng);
        filter: hue-rotate(0deg);
    }
    to{
        transform: rotate(360deg);
        filter: hue-rotate(360deg);
    }
}



.d1::before,.d1::after{
    content: "";
    position: absolute;
    background: #000;
    border-radius: 50%;
    z-index: 100;
}
/* 挡住d1成环形 */
.d1::before{
    top: 6px;
    left: 6px;
    bottom: 6px;
    right: 6px;
}
/* 圆周围的发光效果 */
.d1::after{
    top: 0;
    left: 0;
    bottom: 0;
    right: 0;
    background: linear-gradient(to right,transparent 50%,red);
    filter: blur(30px);
    z-index: 1;
}